Muscle Contractions

Contractions, put simply, are the basic action of any muscle. A contraction is a change in a muscle by which it becomes thickened and shortened after the brain sends signals to nerve cells telling them do contract a specific muscle or muscles. Surprisingly, a contraction is a complex human action and reaction, yet it is such a breeze to understand the basic meaning of the word. Throughout this essay I will give you extensive details about the process of muscle contractions and the parts of the human anatomy that make the whole thing possible. You’d be surprised about all of the work that goes into a process that takes milliseconds to conceive the end result, a muscle contraction.

One day, after Jimi finished a long day at work in the office, he stopped at the gym close to his house just like every other Wednesday night. Jimi’s favorite workout was the vertical bench press machine; so of course, he went to it first just after signing in. But before he started to pump some iron, Jimi remembered to stretch first, so he didn’t pull any muscles. First, he grabbed some lightweight dumbbells and curled them to warm his muscles up; this prevents tearing of the muscle. Next, he was able to do cross body arm stretches and some behind the head arm stretches by bending one arm behind his head and using the other hand to lightly push down on the elbow. Finally, Jimi was able to get to the bench press and lift at a heavier weight than normal, thus causing him to build up his guns. The muscles Jimi used during this exercise were all primarily skeletal muscles, also known as striated muscles. Skeletal muscles are exactly what they sound like, muscles that are connected to bones and are responsible for the rotation of bones around joints, moving the eyes, and serve as valves to check the blood flow. Ultimately, it is responsible for movement. You know when you’re using your skeletal muscles because these are the muscles that you can see and...

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...Christopher Couchell
Muscle Physiology
Purpose:
The Purpose of this exercise is to understand how muscle twitch, contract and react to different activities.
Exercise 1: Muscle Twitch
A. What is a muscle twitch?
A muscle twitch is the fasciculation , or "muscle twitch", is a small, local, involuntary musclecontraction and relaxation visible under the skin.
B. According to the graphs, which muscle has the fastest twitch? Why?
The lateral rectus eye muscle has the fastest twitch. It has the shortest latent period, or the shortest period of time between the stimulus and its response.
C. What is the latent period and why does it occur?
The latent period is the first stage of a muscle twitching. It is the time that elapses between the stimulus and its response.
Exercise 2: Treppe
A. Why is treppe an important phenomenon for athletes to understand?
The phenomenon in which the contraction strength of a muscle increases, due to increased calcium availability and enzyme efficiency during the warm-up. An athlete can perform better when he or she knows when her performance will peak. In this case the muscle will reach its maximum potential after a warm-up.
B. Physiologically, what causes treppe to occur?
A treppe occurs when more forcefully after it has...

...NAME_____________________
LAB 6: Skeletal Muscle Physiology
Electrical Stimulation
1. Complete the following statements by filling in your answers on the appropriate lines below.
A motor unit consists of a (a) and all the (b) it innervates. Whole musclecontraction is a(n) (c) response. In order for muscles to work in a practical sense, (d) is the method used to produce a slow, steady increase in muscle force. When we see the slightest evidence of force production on a tracing, the stimulus applied must have reached (e) . The weakest stimulation that will elicit the strongest contraction that a muscle is capable of is called the (f) . That level of contraction is called the __(g)__ . When the (h) of stimulation is so high that the muscle tracing shows fused peaks, (i) has been achieved.
a.
b.
c.
d.
e.
f.
g.
h.
i.
2. Name each phase of a typical muscle twitch, and, on the following line, describe what is happening in each phase.
a.________________________
____________________________________________________________
________________________________
b.________________________
____________________________________________________________
________________________________
c.________________________...

...Preventing Muscle Cramps Caused By Dehydration
John Doe
GEN/200
April 18, 2011
John Deere
Preventing Muscle Cramps Caused By Dehydration
Muscles cramps and spasms can be annoying. If the body is not taking in enough daily fluids it can cause major health issues in a short amount of time. Fluids as well as other contributing factors such as age, has a large influence on muscles. People can often suffer from muscle weakness and cramping from dehydration. Exercising can also reduce the body’s hydration levels that can create fatigue in the muscles. If not properly hydrated muscles can feel discomfort when trying to contract for movement. These are just some of the symptoms caused by dehydration. One must provide enough fluids each day to ensure muscles can function properly and prevent muscle fatigue.
Daily issue of Muscle Cramps
As humans grow older the muscles are more prone to cramps, spasms, stiffness, aches, and pains. Without proper hydration muscles can stiffen when they are stationary for along time.
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...Static Contraction Weight Lifting
Going to the gym, I notice people blindly bouncing from weight machine to machine until they do enough repetitions to make the target muscle group tired. Isn’t that the goal of working out? Tiring yourself out so your body grows more muscle? No, unfortunately that is not how it works. Working out with the purpose of gaining muscle and strength requires more than just getting “tired” and it must be more than just a habit. One of the best ways to train your body if you want to expect muscular gains is to maximize the intensity of your workout rather than the number of reps. The biggest thing that many people misinterpret is the correlation between “time is takes to lift weight” and “muscle gains”. It only makes sense that the longer you lift weights, the more your muscles will be trained, right? But is that really true? Why is it that a person who can bench one rep of 300lbs. is bigger than a person who can bench three reps of 100lbs? Sure, they both lifted the same amount of weight total, but the bigger person took less time to lift it. This concept can be directly applied to your weight lifting regime in the gym—this system is called static contraction weight lifting.
There are two training methods that are integrated in static contraction training: the isotonic method and the isometric method of training. The isotonic...

...﻿Epimysium- covers the entire muscle
Perimysium- covers..?
Endomysium- covers the individual muscle fibers
Sarcomere- smallest contractile element of muscle fiber, extends from z-line to z-line
Myofilament- responsible for contraction
Striated- the color variations on the muscle fiber. Has to do with the amount of protein and the way it reflects light.
Myosin- globular protein
Bulb like heads come in contact with the active sites on actin
Active sites are not exposed when in the resting position.
Tropomysin- the regulatory protein the hides the active sites when not stimulated
Sarcoplasmic reticulum- lines either side of the t-tubule
T-tubule- comes from the muscle fiber, the z-disks
T tubule and the cistaline? make up the triad
Skeletal musclecontraction
Must be stimulated by action potentials, at a nerve ending
Propagate an electoral current or action potential sarcolemma (surrounding area of the muscle)
Have a rise in intracellular Ca2+ level; the final trigger for contraction
Linking the electoral signal to the contraction is excitation-contraction coupling
Very tightly coupled
In muscle its usually all or nothing
Neuromuscular junction
Each muscle has a motor neuron that innervates
Attaches to muscle fibers via external...

...LAB 9: Skeletal Muscle Physiology
Electrical Stimulation
1. Complete the following statements by filling in your answers on the appropriate lines below.
A motor unit consists of a ___1___ and all the ___2___ it innervates.
Whole musclecontraction is a(n) ___3___ response.
A ___4___ is the response of a muscle to a single, brief threshold stimulus.
When the frequency of stimulation is so high that the muscle tracing shows fused peaks, ___5___ has been achieved.
___6___ is the stimulus strength at which the first observable musclecontraction occurs
The phenomenon, called ___7___, brings more and more muscle fibers into play
1. _motor neuron___
2. _muscle fibers___
3. _involuntary___
4. _Muscle twitch___
5. _complete tetanus___
6. _threshold stimulus___
7. _recruitment___
KEY:
A. complete tetanus
B. involuntary
C. motor neuron
D. muscle fibers
E. muscle twitch
F. recruitment
G. threshold stimulus
H. voluntary
2. Name each phase of a typical muscle twitch, and, on the following line, describe what is happening in each phase.
a. _Latent period___
_the first moments after stimulation when excitation contraction is occuring___
b. _Period of Contraction___
_the...